Disclination lines in glasses

It is shown that line defects are topologically stable in disordered condensed matter, and that they are disclinations, associated with rotation distortions. These disclinations are constructed explicitly in continuous random networks, where they are shown to be uninterrupted lines threading through the odd-numbered rings of bonds. Their topological stability is associated with the fact that the rotation group is not simply connected. The disclinations are of one type only and are characterized by oddness rather than by intensity as in crystals; they are described by the two-element group Zr2.